Exhaust heat exchangers in exhaust gas recirculation systems often use the liquid coolant of the internal combustion engine to cool the exhaust gas. However, air that is heated in heat exchange with the exhaust and then used to heat the passenger compartment is often used in vehicle heating. An exhaust heat exchanger in an exhaust gas recirculation system is disclosed in U.S. Pat. No. 2,408,846, where the surrounding air cools exhaust air by flowing around the housing of the exhaust heat exchanger provided with cooling ribs on the outside. Also, DE 199 30 416 A teaches a cooling device in which the exhaust recirculation line is passed through the intake line of the internal combustion engine in order to cool the exhaust with the intake air.
The present invention is directed toward improving upon exhaust heat exchangers which use intake air.